5-imino-1,2,4-triazines and their production

ABSTRACT

NOVEL 5-IMINO-1,2,4-TRIAZINE COMPOUNDS OF THE FORMULA   3-R2,4-R1,5-(HN=),6-R-4,5-DIHYDRO-1,2,4-TRIAZINE IN WHICH R IS AN ALIPHATIC, ARYLALIPHATIC, AROMATIC OR HETEROCYCLIC RADICAL WHICH MAY BE SUBSTITUTED BY HYDROXY, HALOGEN, ALKYL AND/OR NITRO, R1 IS AN ALIPHATIC HYDROCARBON RADICAL, AMINO, ALKYLAMINO OR DIALYLAMINO, R2 IS HYDROGEN OR AN ALIPHATIC HYDROCARBON RADICAL, AND X IS OXYGEN, SULFUR OR NR3 WHERE R3 IS FOR HYDROGEN OR AN ALIPHATIC HYDROCARBON RADICAL, POSSESS OUTSTANDING HERBICIDAL, ESPECIALLY SELECTIVE HERBICIDAL ACTIVITY, AND FURTHERMORE ARE INTERMEDIATES FOR THE PREPARATION OF OTHER HERBICIDAL COMPOUNDS. THE INVENTION ALSO PROFIVES A NOVEL PROCESS FOR MAKING THE NOVEL 5-IMINO-1,2,4-TRIAZINE COMPOUNDS BY REACTING A CORRESPONDING A-IMINONITRILE WITH A HYDRAZINE DERIVATIVE.

United States Patent 3,752,808 -IMINO-1,2,4-TRIAZINES AND THEIRPRODUCTION Manfred Jautelat and Hans-Joachim Kabbe, Leverkusen, and KurtLey, Odenthal-Globusch, Germany, assignors to Bayer Aktiengesellschaft,Leverkusen, Germany No Drawing. Filed Jan. 19, 1971, Ser. No. 107,823Claims priority, application Germany, Jan. 24, 1970, P 20 03 144.1 Int.Cl. C07d 55/18 US. Cl. 260-2495 18 Claims ABSTRACT OF THE DISCLOSURENovel 5-imino-l,2,4-triazine compounds of the formula A In I...

in which R is an aliphatic, arylaliphatic, aromatic or heterocyclicradical which may be substituted by hydroxy, halogen, alkyl and/ ornitro,

R is an aliphatic hydrocarbon radical, amino, alkylamino ordialkylamino,

R is hydrogen or an aliphatic hydrocarbon radical, and

X is oxygen, sulfur or NR where R is for hydrogen or an aliphatichydrocarbon radical,

possess outstanding herbicidal, especially selective herbicidalactivity, and furthermore are intermediates for the preparation of otherherbicidal compounds.

The invention also provides a novel process for making the novel5-imino-1,2,4-triazine compounds by reacting a correspondinga-iminonitrile with a hydrazine derivative.

The present invention relates to novel 5-imino-1,2,4- triazinecompounds, to herbicidal compositions containing them, and to their useas herbicides. In diflerent aspect the invention relates to a novelchemical process which can be used to prepare said novel compounds.

The present invention provides 5-imino-1,2,4-triazine derivatives of thegeneral formula R is preferably alkyl of from l-6 carbon atoms or amino,R is preferably hydrogen or alkyl of from 1-6 carbon atoms, and X ispreferably oxygen or sulfur.

The new 5-imino'-1,2,4-triazine derivatives according to the inventionare valuable intermediates for the preparation of herbicidal activecompounds. By hydrolysis of the imino group, for example by heating withdilute hydrochloric acid, the 5-irnino-l,2,4-triazine derivatives can beconverted into the appropriate 1,2,4-triazine-5- ones, the herbicidalpotency of which is known (cf. Naturice wissenschaften 55, 1446 (1968),as well as Japanese patent specification 547,317). For example,3-mercapto-4-amino- 5-imino-6-tert.-butyl-1,2,4-triazine can behydrolyzed by boiling under reflux for one hour with 1 N hydrochloricacid, with the formation of 3-mercapto-4-amino-6-tert.-butyl-1,2,4-triazine-5-one, which can at 20 C. be methylated with methyliodide in the presence of sodium hydroxide be converted into3-methylmercapto-4-arnino- 6-tert.-butyl-.1,2,4-triazine-5-one which isknown as a particularly elfective herbicide.

The invention accordingly provides intermediates from which knownherbicidal compounds can be prepared.

Moreover, the new 5-imino-1,2,4-triazine derivatives according to theinvention also exhibit themselves strong herbicidal properties and cantherefore be used for the control of weeds. The term weeds is usedherein in the widest sense to mean all plants which grow in places wherethey are not desired. Whether the active compounds according to theinvention act as total or selective herbicides depends chiefly on theamount used.

The invention also provides a novel process for the production of acompound of Formula 1 above.

It is known that 1,2,4-triazine-5-one derivatives can be prepared byreaction of a-ketonic acids with hydrazine derivatives (cf. TheChemistry of Heterocyclic Compounds, A. Weissberger, vol. 10, 44,Interscience Publishers, Inc., New York, 1956). However, since thea-ketonic acids are accessible with difficulty or by multistepsyntheses, such as e.g. trimethylpyruvic acid, this process is of onlylimited importance. It is also known that5-imino-6-phenyl-1,2,4-triazines which can readily be converted intoappropriate 1,2,4-triazine-5-ones by hydrolysis of the imino group areobtained from benzoylcyanides and hydrazines derivatives (see Belgianpatent specification 735,318). This method fails, however, when5-imino-6-alkyl-1,2,4-triazines are to be prepared which have importanceas intermediates for the synthesis of -6-alkyl-1,2,4-triazine-5-ones,since the acylcyanides concerned split ofi' preferentially hydrogencyanide when they are reacted with hydrazine derivatives (cf. Chem. Ber.88, 117 (1955)).

In the process of this invention the compounds of Formula I are preparedby reacting an a-iminonitrile of the general formula in which R and Rmay be the same or different and each is defined as 'R is defined above,with a hydrazine derivative of the general formula NH1N=CNHR1 (III) inwhich R R and X are defined as above, in the presence of an organicsolvent and in the presence of an acid.

It is very surprising that the a-iminonitriles of Formula H when reactedwith hydrazine derivatives of Formula I II behave quite differently fromthe corresponding acylcyanides (that is, a-ketonitriles). Whereasacylcyanides react with hydrazine derivatives with, above all, thesplitting olf of hydrogen cyanide (cf. Chem. Ber. 88, 1117 (1955)), thea-iminonitriles concerned do not lose the nitrile group when reactedwith hydrazine derivatives. On the contrary, the 1,2,4-triazine systemis formed in almost quantitative reaction in the form of the S-imino-1,2,4-triazines of Formula I. By hydrolysis, these S-imino-1,2,4-triazines can, further, readily be converted into1,2,4-triazine--ones. Since the a-iminonitriles required, for example2-N-tert.-butylimino-3,3-dimethylbutyronitrile (cf. Chem. Ber. 1022,1447 (1969)), are more readily accessible as starting materials than theappropriate u-ketonic acids, the process according to the inventionexhibits considerable advantages compared with the process starting fromu ketonic acids. The present invention therefore represents asubstantial enrichment of the art.

If 2-N-tert.-butylimino-3,3-dimethylbutyronitrile and thiocarbohydrazidehydrochloride are used as starting materials, the reaction course can berepresented by the following formula scheme:

(5(C'Ha):

The a-iminonitriles used as starting materials are defined generally byFormula II.

R and R stand preferably for alkyl with 1 to carbon atoms, e.g., methyl,isopropyl, butyl, or decyl.

Some of the a-iminonitriles are known. They can be prepared either bydimerisation of isonitriles under the catalytic influence of Lewis acidssuch as boron trifiuoride (cf. Ber. 102, 1447 (1969)) or by cationicallycatalysed reaction of isonitriles with nitriles (J. Org. Chem. 34,40404046 (1969)). The compounds which are not yet known can be preparedaccording to the same methods.

As examples of the a-iminonitriles to be used according to theinvention, reference may be made to the compounds described in theabove-mentioned literature, and preferably those a-iminonitriles whichcan be prepared by dimerisation of the following tert.-alkylisonitriles:tert.- butylisonitrile, 1,1-dimethyl-propylisonitrile,1,1,3,3-tetramethylbutylisonitrile, l-methyl 1 cyclohexylisonitrile,l-ethyl-l-cyclopentylisonitrile and l-methyl-l-cyclooctylisonitrile.

The hydrazine derivatives used as starting materials are definedgenerally by Formula III.

The hydrazine derivatives of Formula III are known. As examples of thehydrazine derivatives which can be used according to the invention,there may be mentioned in particular: thiosemicarbazide,S-methyl-thiosemicarbazide, thiocarbohydrazide,S-methylthiocarbohydrazide, 4-methylthiosemicarbazide andcarbohydrazide.

All inert polar organic solvents are suitable for use as the solvent.These include for example alcohols with 1-6 carbon atoms, preferablyethanol, as well as strongly polar solvents such as dimethyl sulphoxide,dimethyl formamide or hexamethylphosphoric acid triamide.

The presence of acidic catalysts is of importance in the reactionaccording to the invention.

Suitable acidic catalysts include for example Lewis acids such as borontrifluoride, aluminium chloride or tetrachloride; organic acids such astrifluoroacetic acid; and preferably inorganic acids, such ashydrochloric acid, nitric acid, sulphuric acid or phosphoric acid. Ithas proved particularly expedient to use the acid combined with thehydrazine derivative as salt.

The reaction temperatures can be varied within a fairly wide range. Ingeneral, the reaction is carried out at from to +150 C., preferably 0 to100 C.

In the carrying out of the process according to the invention,a-iminonitrile and hydrazine derivative are, in general, used in a molarratio from 2:1 to 1:2, preferably in a ratio of approximately 1:1. Theacid, with reference to the hydrazine derivative, is generally used in amolar ratio from 0.3:1 to 2:1, preferably in a ratio of approximately1:1. In general, the reaction is begun at low temperatures, and heatingto higher temperatures is then efiected slowly. The working up may takeplace in customary manner for example by precipitation of the reactionproducts with water, filtration and recrystallization.

Moreover, the new 5-imino-1,2,4-triazine derivatives according to theinvention also themselves exhibit strong herbicidal properties and cantherefore be used for the control of weeds. The term weeds is usedherein the widest sense to mean all plants which grow in places wherethey are not desired. Whether the active compounds according to theinvention acts as total or selective herbicides depends chiefly on theamount used.

The active novel compounds of this invention can be used for example inthe case of the following plants: dicotyledons, such as mustard(Sinapsis), cress (Lepidium), cleaver (Galium), common chickweed(Stellaria), camomile (Matricaria), smallflower (Galinsoga), fathen(Chenopodium), stinging nettle (Urtica), groundsel (Senecio), cotton(Gossypium), beets (Beta), carrots (Daucus), beans (Phaseolus), potatoes(Solanum), coffee (Cofiea); monocotyledons, such as timothy (Phleum),bluegrass (Poa), fescue (Festuca), goosegrass (Eleusine), foxtail(Setaria), ryegrass (Lolium), cheat (Bromus), barnyard grass(Echinochloa), maize (Zea), rice (Oryza), oats (Avena), barley(Hordeum), Wheat (Triticum), millet (Panicum), sugar-cane (Saccharum).

The active compounds of the invention can be converted into the usualformulations, such as solutions, emulsions, suspensions, powders, pastesand granulates. These may be produced in known manner, for example bymixing the active compound with extenders, that is, liquid or soliddiluents or carriers, optionally with the use of surface-active agents,that is, emulsifying agents and/or dispersing agents. In the case of theuse of water as an extender, organic solvents can for example also beused as auxiliary solvents.

As liquid diluents or carriers, there are preferably used aromatichydrocarbons, such as xylenes or benzene, chlorinated aromatichydrocarbons, such as chlorobenzenes, paraflins, such as mineral oilfractions, alcohols, such as methanol or butanol, or strongly polarsolvents, such as dimethyl formamide or dimethyl sulphoxide, as well aswater.

As solid diluents or carriers, there are preferably used ground naturalminerals, such as kaolins, clays, talc or chalk, or ground syntheticminerals, such as highly-dispersed silicic acid or silicates.

Preferred examples of emulsifying agents include nonionic and anionicemulsifiers, such as polyoxyethylenefatty acid esters,polyoxyethylene-fatty alcohol ethers, for example, alkylarylpolyglycolethers, alkyl sulphonates and aryl sulphonates; and preferred examplesof dispersing agents include lignin, sulphite waste liquors and methylcellulose.

The active compounds of the invention may be present in the formulationsin admixture with other active compounds.

The formulations contain, in general, from 0.1 to 95, preferably from0.5 to 90, percent by weight of active compound.

The active compounds of the invention may be used as such, or in theform of their formulations or of the application forms preparedtherefrom, such as ready-touse solutions, emulsions, suspensions,powders, pastes and granulates. Application may be effected in the usualmanner, for example by spraying, squirting, scattering, dustmg orwatering.

The active compounds may be used in both the preemergence process andthe post-emergence process. It is particularly expedient that the weedsbe controlled in the early stage of development.

The invention also provides a herbicidal composition containing asactive ingredient the compound of Formula I in admixture with soliddiluent or carrier or in admixture with a liquid diluent or carriercontaining a surface-active agent.

The invention also provides a method of combating sifier was added andthe concentrate was then diluted weeds which comprises applying to theweeds or weed with water to the desired concentration. habitat thecompound of Formula I alone or in the form Seeds of the test plants weresown in normal soil and, of a composition containing as activeingredient the comafter 24 hours, watered with the preparation of theactive pound of Formula I in admixture with a solid or liquid 5compound. It was expedient to keep constant the amount diluent orcarrier. The invention is illustrated by the of water per unit area. Theconcentration of the active following examples. compound in preparationwas of no importance, only EXAMPLE A the amount of active compoundapplied per unit area being decisive. After three weeks, the degree ofdamage to the test plants was determined and characterised by Solvent! 5Parts y Welght acetone the values 0-5, which have the following meaning:Emulsifier: 1 part by weight alkylaryl polyglycol ether Post-emergencetest 0 No elfect. To produce a suitable preparation of active compound,1 Slight damage or delay in growth 1 part by weight of active compoundis mixed with the l5 2 Marked damage or inhibition of growth. statedamount of solvent, the stated amount of emulsifier 3 Heavy damage andonly deficient development added and the concentrate is then dilutedwith water or only 50% emerged to the desired coilcentratlon' 4 Plantspartially destroyed after germination or Test plants WhlCh have a he1ghtof about 5-15 cm. are only emerged sprayed with the preparation of theactive compound t t ed such a way, that the amount of active compoundper 20 5 Plan 3 completely dead or no emerg unit area as given in thefollowing table, is used. Depend- The active compounds, the amountsapplied and the ing on the concentration of the spraying liquor, theresults obtained can be seen from the following table:

TABLE.PRE-EMERGENCE-TEST Amount of active compound applied, Echino-Cheno- Galin- Stel- Matri- Active compound kg./ha. Oats Cotton WheatMaize chloa podium Sinapis soga lan'a caria Lolium NH 10 4-5 4 4 4 5 5 55 5 5 4-5 5 4-5 3-4 3-4 4 5 4-5 5 5 5 5 4 t 5 H 1 5? 3 i i "*3 i *2 t 22 ii i 4 0 I 0. 525 1 1 0 1 3 2 1 4 4-5 4-5 0 SCH 0.3125 1 0 0 o 2 1 o 32 2 0 3-methylmercapto-4- amino-5-imino-6-tert.- butyl-l 2, 4-triazine.

amount of water ranges from 1000-2000 l./ha. After EXAMPLE 1 three.Weeks the degre? of damage to the plant.s is 40 Preparation of3-mercapto-4-amino-5-imino-6-tert. termmed and characterlsed by thevalues 0-5, which have butyl-1,2,4-triaz1ne the followmg meanings: NH 0No efiect. I 1 A few slightly burnt spots. (crime N NH2 2 Marked damageto leaves. 1 3 Some leaves and parts of stalks partially dead. SH 4Plant partially destroyed. (V) 5 Plant completely dead. 142.5 g. (1mole) thiocarbohydrazide hydrochloride were dissolved in 500 ml.dimethyl sulphoxide and reacted The active compounds, theirconcentrations and rein one hour with 166 g. (1 mole)2-tert.-butylimino-3,3- sults obtained can be seen from the followingtable: dimethylbutyronitrile, with cooling to 20 C. Stirring wasTABLE.-POSTEMERGENCE-IEST Amount of active compound applied, Cot-Eehino- Cheno- Galin- Stel- Matri- Active compound kg./ha. Oats tonWheat Beans ehiloa podium Sinapis soga laria Urtica caria Daucus .CH 5 53 2 9 N 0.125 2 0 o a 4 5 4-5 5 4 5 0 1 SCH 3 3-methylmercapto-4-amino-5-imino-6-tert.- butyl-l, 2, 4-triazine.

EXAMPLE B afterwards effected for one hour before the reaction P tproduct was precipitated with 1 litre of ice Water. After re'emergenceest recrystallization from ethanol, 3-mercapto-4-amino-5- Solvent: 5parts by weight acetone imino-6-tert.-butyl-1,2-4-triazine of themelting point 181 Emulsifier: 1 part by weight alkylaryl polyglycolether Was Obtained- To produce a suitable preparation of activecompound, Yield: 150 (7.5% of the theory) 1 part by weight of activecompound Was mixed with The following Table 1 shows the yields ofS-mercaptothe stated amount of solvent, the stated amount of emul- 4amino 5 imino-6-tert.-butyl-'1,2,4-triazine when the same reaction wascarried out using various solvents, temperatures and catalysts:

iodide were added at 20 C. The reaction mixture was subsequently stirredat 20 C. for further 4 hours. The

TABLE 1 Catalyst (1 molar Yield, Solvent Temp., CJtime, hoursequivalent) percent M.P., C.

Ethyl alcohol 20l1 hour plus 9011 hour... H01 (as salt) 80 179-181Dimethyl formamide 50 178-180 Dimethyl sulphoxide 20l2 hurs HNOa (assalt) 51 9-180 Do 2011 hour BFa-O(C2H5)z 12 179-180 Do do CFa-COOH 30178-180 (a) Hydrolysis:

10 parts by weight 3-mercapto-4-amino-5-irnino-6-tert.-butyl-l,2,4-triazine were heated to 100 C. for 2 hours with 80 parts byweight ethanol and 100 parts by weight l-normal hydrochloric acid. Aftercooling to C., the crystalline reaction product separated, was filteredoff with suction and was dried. There were obtained 9.3 parts by weight3 mercapto-4-amino-6-tert.-butyl-1,2,4-triazine-5- one of the meltingpoint 215-2l7 C.

Yield: 93% of the theory.

This hydrolysis can also be carried out in a one-pot process immediatelyfollowing the reaction of 2-tert.- butyl-imino 3,3 dimethylbutyronitrilewith th'iocarbohydrazide hydrochloride without intermediate isolation ofthe 3 mercapto 4-amino-5-imino-6-tert.-butyl-1,2,4- triazine.

(b) Methylation:

(CH3)3C i son, (VII) (came N SCH:

'Analogously with Example 1, using S-methylthiocarbohydrazidehydrochloride, there was obtained3-methylmercapto-4-amino-5-imino-6-tert.-butyl-1,2,4 triazine of themelting point 154-155 C.

The same product can be prepared by direct methylation of the3-mercapto-4-amino-6-tert.-butyl-1,2,4-triazine described in Example 1,as follows:

4 parts by weight 3-mercapto-4-amino-5-imino-6-tert.- buty1-1,2,4triazine were dissolved in a mixture of 11 parts by weight 2-normalsodium hydroxide solution and 4 parts by weight methanol and, possiblyafter filtering off a little undissolved matter, 3.2 parts by weightmethyl reaction product crystallized out, was filtered off with suctionand was dried. There were obtained 3.8 parts by weight (89% of thetheory) 3-methylmercapto-4-amino- 5 imino 6 tert.-butyl-1,2,4-triazineof the melting point 152-154 C. If the intermediate isolation of3-mercapto-4- amino-5-imino=6-tert. butyl- 1,2,4-triazine was dispensedwith the methylation described above can also be carried out in aone-pot method.

7.1 parts by weight thiocarbohydrazide hydrochloride and 8.3 parts byweight 2-tert.-butylimino-3,3-dimethylbutyronitrile were stirred for 1hour at room temperature in 5 parts by weight dimethyl sulphoxide. 5parts by weight 2-norma1 sodium hydroxide solution were then added,brief evacuation was effected, and 8.5 parts by weight methyl iodidewere added at 0 C. The reaction product crystallized out, was filteredoff with suction and was recrystallized from ethanol. There wereobtained 4.4 parts by weight '3-methylmercapto-4-amino-5-irnino-6-tert.-butyl-1,2,4-triazine of the melting point l54-l55 C. Yield: 41% ofthe theory.

EXAMPLE 3 Preparation of 3-hydroxy-4-amino-5-imino-6-tert.-butyl-1,2,4-triazine N CH (IX) 166 parts by weight2-tert.-butylimino-3,B-dimethylbutyronitrile and 126 parts by weightcarbohydrazide hydrochloride were heated to C. for 1 hour in 400 partsby weight dimethyl sulphoxide. From the clear solution, 195 parts byweight of colourless substance were precipitated with water. Afterrecrystallization from ethyl alcohol, 98 parts by weight (53% of thetheory) 3-hydroxy-4-amino-5-imino-6-tert.-buty1-1,2,4-triazine of themelting point 182-184 C. were obtained.

EXAMPLE 4 Preparation of 3-mercapto4-methyl-5-imino-6-tert.-

butyl-l,2,4-triazine \N/ SH (X) 166 parts by weight 2-tert.-butylimino3,3-dimethylbutyronitrile and 141 parts by weight4-methylthiosemicarbazide hydrochloride were heated to 100 C. for onehour in 400 parts by weight dimethyl sulfoxide. After precipitation ofthe reaction product with water and recrystallization from alcohol,there were obtained 62 parts by weight (31% of the theory)3-mercapto-4-methyl-5- imino-6-tert.-butyl-1,2,4-triazine of the meltingpoint 170- 172 C.

It will be understood that the specification and examples areillustrative but not limitative of the present invention and that otherembodiments within the spirit and scope of the invention will suggestthemselves to those skilled in the art.

9 What is claimed is: 1. -imino-1,2,4-triazine compound of the formula\N/ x-rt,

in which R is alkyl of from 1 to carbon atoms,

R is alkyl of from 1 to 6 carbon atoms or amino,

R is hydrogen or alkyl of from 1 to 6 carbon atoms, and X is oxygen orsulfur.

in which R is alkyl of from 1 to 10 carbon atoms, R is alkyl of from 1to 6 carbon atoms or imino, R, is hydrogen or alkyl of from 1 to 6carbon atoms, and X is oxygen or sulfur; which process comprisesreacting an u-iminonitrile of the formula R-O-OEN 10 in which R isdefined as above and R is alkyl of from 1 to 10 carbon atoms;

with a hydrazine compound of the formula in which R R and X are definedas above, in the presence of an organic solvent and in the presence ofan acid.

9. Process as claimed in claim 8 in which the reaction is carried out ata temperature of from about 20 C. about 150 C.

10. Process as claimed in claim 9 wherein the reaction temperature isbetween 0 and C.

11. Process as claimed in claim 8 in which said solvent is ethylalcohol, dimethyl sulfoxide or dimethyl formamide.

12. Process as claimed in claim 8 in which said hydrazine compound is inthe form of its hydrochloride.

13. Process as claimed in claim 8 wherein the molar ratio of saidot-iminonitrile to said hydrazine compound is from 2:1 to 1:2.

14. Process as claimed in claim 13 wherein said molar ratio is about1:1.

15. Process as claimed in claim 8 wherein the molar ratio of said acidto said hydrazine compound is from 0.3 :1 to 2: 1.

16. Process as claimed in claim 15 wherein said molar ratio is about1:1.

17. Process as claimed in claim 8 wherein said acid is trifiuoroaceticacid.

18. Process as claimed in claim 8 is carried out in the presence ofboron trifluoride etherate.

References Cited UNITED STATES PATENTS 3,586,680 6/1971 Meiser et al.260-2495 JOHN M. FORD, Primary Examiner US. Cl. X.R.

